Two-piece female swimsuit for competition swimming

ABSTRACT

A female two-piece swimsuit ( 1 ) with a lower halfsuit ( 3 ) forming a tubular first trunk portion ( 5 ) having an upper slip-in aperture ( 6 ) and two tubular thigh portions ( 8 ) joining each other in a first crotch portion ( 9 ), and with an upper halfsuit ( 2 ) forming a second tubular trunk portion ( 11 ) having two leg apertures ( 12 ), a second crotch portion ( 13 ) extending between the two lower leg apertures ( 12 ), a neck opening ( 14 ) opposite the second crotch portion ( 13 ) and two lateral shoulder openings ( 15 ), wherein the upper halfsuit ( 2 ) is slipped over the lower halfsuit ( 3 ) so that the thigh portions ( 8 ) of the lower halfsuit portion ( 3 ) extend through the lower leg apertures ( 12 ) of the upper halfsuit ( 2 ) on the outside of the upper halfsuit ( 2 ) and, in an overlap region ( 15 ), the second trunk portion ( 11 ) externally wraps the first trunk portion ( 5 ) and the second crotch portion ( 13 ) externally wraps the first crotch portion ( 9 ), wherein the upper and lower halfsuits ( 2, 3 ) are in slidable contact to each other in said overlap region ( 15 ).

The present invention relates to female swimsuits for swimming and particularly for competition swimming.

In the past years, in competitive swimming, the development of swimsuits focuses mainly on two principal goals, i.e. the reduction of drag between the external surface of the swimsuit and the water and a hoop-compression of the muscular structure of the swimmer in the region of the legs and body trunk core.

In order to reduce the friction between the swimmer and the water, several stretchable fabrics with an extremely smooth and water repellent external surface texture have been proposed and successfully used. Moreover full-body swimsuits have been developed in order to extend the beneficial hydrodynamic features of the smooth and water repellent fabric over nearly the entire body surface of the athlete.

The muscle compression has been achieved by using swimsuits made of stretchable garment material with a comparatively high coefficient of elasticity and by dressing the swimmer with such a size of swimsuit that the stretching of the fabric and resulting reaction hoop force bring about a considerable radial compression of the swimmer's body trunk and legs. The muscular compression assists the maintenance of a desired posture in water and reduces undesired loose muscle movements and accumulation of lactic acid in the muscles throughout the body portions that are covered and compressed by the fabric of the swimsuit.

Existing elite level compression swimsuits still have some drawbacks regarding the athletes' muscle compression, the wearing comfort and the freedom of movement of the swimmer.

Specifically, the use of existing elite level compression swimsuits are a challenge for many female swimmers. Putting on the swimsuits is difficult and can take up to 25 minutes, requiring a high amount of physical strength and energy. The compression provided by the swimsuit often applies extreme pressure on the shoulders, causing fatigue and restriction of the freedom of movement of the shoulders. Finding the correct size which is optimal for both the upper body region and the lower body region of the female swimmer is difficult due to the different muscle mass/structure and body shapes. The shape ratio between the upper body region and the lower body region of female swimmers differs greatly and with known female compression swimsuits it is difficult finding a swimsuit which applies the correct compression in exactly those locations where it is needed, without compromising freedom of movement and wearing comfort.

A further need is to reconcile the compression function of the swimsuit fabric with the swimmers' need to fully bend his body at the hip during takeoff from the starting block and during the turns.

The objective of the present invention is therefore to provide an improved female swimsuit that better addresses at least some of the described needs.

These and other objectives are achieved by a two-piece female swimsuit according to claim 1.

Advantageous and preferred embodiments are the object of the dependent claims.

According to an aspect of the invention, a female two-piece swimsuit, particularly for competition swimming, comprises an upper halfsuit and a lower halfsuit separate from the upper halfsuit and which are adapted to be combined together to make the swim suit.

The lower halfsuit comprises a first shell made of a flexible stretchable fabric and forming:

a first tubular trunk portion shaped/intended to cover a lower region of the torso of the swimmer and having an upper slip-in aperture and a lower end opposite the slip-in aperture,

two tubular thigh portions shaped/intended to cover each an upper region of a respective thigh of the swimmer and extending from the lower end of the first trunk portion and joining each other in a first crotch portion extending between the thigh portions from an anterior side of the first trunk portion to a rear side of the first trunk portion.

The upper halfsuit comprises a second shell made of a flexible stretchable fabric and forming:

a second tubular trunk portion shaped/intended to cover a region of the torso and the chest of the swimmer and having two lower leg apertures intended for the swimmers' legs to extend therethrough,

a second crotch portion extending between the two lower leg apertures from an anterior side of the second trunk portion to a rear side of the second trunk portion,

one neck opening formed on an upper side of the upper halfsuit opposite the second crotch portion and intended for a swimmer's neck to extend therethrough,

two lateral shoulder openings formed on opposite sides with respect to the neck opening and intended for the swimmers' shoulders to extend therethrough.

The upper halfsuit is slipped over the lower halfsuit so that the thigh portions of the lower halfsuit extend through the lower leg apertures of the upper halfsuit on the outside of the upper halfsuit and, in an overlap region, the second trunk portion at least partly externally overlaps/wraps the first trunk portion and the second crotch portion externally overlaps/wraps the first crotch portion, wherein the upper halfsuit and the lower halfsuit are in slidable contact to each other in said overlap region.

The two-piece configuration of the swimsuit with separate upper and lower halfsuits that co-operate to cover with slidable overlap the lower region of the torso of the swimmer, has considerable advantages.

The swimsuit can be more easily and comfortably put on. The lower halfsuit can be put on by slipping the swimmers' legs into the upper slip-in aperture and through the thigh portions of the lower halfsuit. Then, the upper halfsuit can be put on by pulling the upper halfsuit over the lower halfsuit and inserting the swimmers' arms through the shoulder apertures and having the swimmers' neck extending through the neck aperture.

A high stretch stiffness of the lower halfsuit, which is desirable for obtaining a desired muscle compression of the thighs and the glutei, does not excessively hinder putting on the lower halfsuit because only the legs need to be pushed in without any involvement of the chest and shoulders of the swimmer.

On the other hand, the upper halfsuit can be made less stiff in order to provide more freedom of movement for the shoulders and arms without jeopardizing the muscle compression and the support for a correct posture of the lower torso.

The absence of tight tubular thigh portions in the upper halfsuit allows the upper halfsuit to be put on more comfortably, thereby saving time and energy of the swimmer. By assembling the swimsuit from two separate parts which can be put on in two separate steps, it becomes easier to find the correct size which is optimal for both the upper body region and the lower body region of the female swimmer.

The configuration of two separate, assembled halfsuits and their sliding interface overlap also allow to better assign the intensity and location of the muscle compression among the upper and lower body regions of the swimmer.

The sliding interface between the second trunk portion and the first trunk portion decouple the displacements and stretch deformations of the upper and lower halfsuits, creating a multiple degree of freedom hinge, and reconciles the compression function of the swimsuit fabric with the swimmers' need to fully bend his body at the hip during takeoff from the starting block and during the turns at the wall.

These and other features and advantages of the present invention shall be made apparent from the accompanying drawings which illustrate embodiments of the invention, and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention.

FIG. 1 illustrates a frontal view of a two-piece female swimsuit according to an embodiment of the invention,

FIG. 2 illustrates a rear view of the two-piece female swimsuit in FIG. 1,

FIG. 3 illustrates a frontal view of the swimsuit in FIGS. 1 and 2 in an assembled configuration in which a lower halfsuit is inserted into an upper halfsuit of the swimsuit,

FIG. 4 shows an exemplary non-linear load-extension (or stress-strain) curve of a fabric of the swimsuit in accordance with an embodiment.

With reference to the figures, a female two-piece swimsuit 1, particularly for competition swimming, comprises an upper halfsuit 2 and a lower halfsuit 3 separate from the upper halfsuit 2 and which are adapted to be combined together to make the swim suit 1.

The lower halfsuit 3 comprises a first shell 4 made of a flexible stretchable fabric and forming a tubular first trunk portion 5 shaped/intended to cover a lower region of the torso of the swimmer and having an upper slip-in aperture 6 and a lower end 7 opposite the slip-in aperture 6, as well as two tubular thigh portions 8 shaped/intended to cover each an upper region of a respective thigh of the swimmer and extending from the lower end 7 of the first trunk portion 5 and joining each other in a first crotch portion 9 extending between the thigh portions 8 from an anterior side of the first trunk portion 5 to a rear side of the first trunk portion 5.

The upper halfsuit 2 comprises a second shell 10 made of a flexible stretchable fabric and forming a second tubular trunk portion 11 shaped/intended to cover a region of the torso and the chest of the swimmer and having two lower leg apertures 12 intended for the swimmers' legs to extend therethrough, as well as a second crotch portion 13 extending between the two lower leg apertures 12 from an anterior side of the second trunk portion 11 to a rear side of the second trunk portion 11.

The second shell 10 forms also one neck opening 14 on an upper side of the upper halfsuit 2 opposite the second crotch portion 13 and intended for a swimmer's neck to extend therethrough, and two lateral shoulder openings 15 formed on two opposite sides with respect to the neck opening 14 and intended for the swimmers' shoulders to extend therethrough.

The upper halfsuit 2 is slipped over the lower halfsuit 3 so that the thigh portions 8 of the lower halfsuit portion 3 extend through the lower leg apertures 12 of the upper halfsuit 2 on the outside of the upper halfsuit 2 and, in an overlap region 15, the second trunk portion 11 externally overlaps the first trunk portion 5 and the second crotch portion 13 externally overlaps the first crotch portion 9, wherein the second trunk portion 11 and the first trunk portion 5 (and, possibly, the first and second crotch portions 9, 13) are in slidable contact to each other in said overlap region 15.

The two-piece configuration of the swimsuit 1, wherein separate upper and lower halfsuits 2, 3 co-operate to cover the lower region of the torso of the swimmer with slidable mutual overlap, has considerable advantages. The swimsuit 1 can be more easily and comfortably put on. The lower halfsuit 3 can be put on by slipping the swimmers' legs into the upper slip-in aperture 6 and through the thigh portions 8 of the lower halfsuit 3. Then, the upper halfsuit 2 can be put on by pulling the upper halfsuit 2 over the lower halfsuit 3 and slipping the swimmers' arms through the shoulder apertures 15 and having the swimmers' neck extending through the neck aperture 14.

A high stretch stiffness of the lower halfsuit 3, which is desirable for obtaining a strong muscle compression of the thighs and the glutei, does not excessively hinder putting on the lower halfsuit 3 because only the legs need to be pushed in without any involvement of the chest and shoulders of the swimmer. On the other hand, the upper halfsuit 2 can be made less stiff than the lower halfsuit 3 in order to provide more freedom of movement for the shoulders and arms without reducing the muscle compression and the support for a correct posture of the lower torso.

By avoiding a formation of tight tubular thigh portions in a single-piece with the upper halfsuit 2, the upper halfsuit 2 can be put on more comfortably, thereby saving time and energy of the swimmer.

By assembling the swimsuit 1 from two separate halfsuits 2, 3 which can be put on in two separate steps, it becomes easier to find the correct size which is optimal for both the upper body region and the lower body region of the female swimmer. The configuration of two separate, assembled halfsuits 2, 3 with a sliding interface overlap also allows to better assign the intensity and location of the muscle compression among upper and lower body regions of the swimmer.

The sliding interface between the second trunk portion 11 and the first trunk portion 5 (and, possibly, the first and second crotch portions 9, 13) decouple the displacements and stretch deformations of the upper and lower halfsuits 2, 3 by creating a multiple DOF sliding hinge. This reconciles the compression function of the swimsuit fabric with the swimmers' need to fully bend his body at the hip during takeoff from the starting block and during the turns.

In an embodiment, in the overlap region 15 between the upper halfsuit 2 and the lower halfsuit 3, the upper halfsuit 2, i.e. the second shell 10, has a stretch stiffness that is lower than a stretch stiffness of the lower halfsuit 3, i.e. the first shell 4. This makes it possible to design the lower halfsuit 3 for the muscle -compression and -support function and to design the upper halfsuit 2 for providing freedom of movement and for covering the chest region of the female swimmer.

In an embodiment, the upper halfsuit 2, i.e. the second shell 10, has, throughout its entire extension, a stretch stiffness that is lower than a stretch stiffness of the lower halfsuit 3, i.e. the first shell 4.

Similarly, the lower halfsuit 3, i.e. the first shell 4, has, throughout its entire extension, a stretch stiffness that is higher than a stretch stiffness of the upper halfsuit 2, i.e. the second shell 10.

In accordance with an embodiment, with the exception of joining lines 16 along which fabric edges of the first shell 4 are connected, the first shell 4 of the lower halfsuit 3 has substantially uniform (though possibly anisotropic) material properties throughout its entire extension. Possibly the first shell 4 is made of a substantially uniform fabric throughout its entire extension.

In accordance with an embodiment, with the exception of joining lines 16′ along which fabric edges of the first second shell 10 are connected and a chest region 17 in an upper region of the anterior side of the upper halfsuit 2, the second shell 10 of the upper halfsuit 2 has substantially uniform (though possibly anisotropic) material properties throughout its entire extension. Possibly the second shell 10 has a substantially uniform fabric throughout its entire extension.

In order to prevent visibility of the bosom of the swimmer through second shell 10 (which may be semi-transparent), a local opaque chest lining 18 is applied from an internal side on the second shell 10 in the chest region 17. Preferably, the chest lining 18 is connected to the second shell 10 only along a peripheral edge 26 of the chest lining 18 and can freely slide and move with respect to the second shell 10 in an internal region of the chest lining 18.

In accordance with an embodiment, in the overlap region 15 between the upper halfsuit 2 and the lower halfsuit 3, both the upper halfsuit 2 and the lower halfsuit 3 consist each of a single layer fabric, and form together a combined double layer shell with a sliding interface between the two layers.

This allows increasing the compression on the glutei and the lower torso in general due to the summed up effects of the stretch stiffness of both individual fabric layers. On the other hand, the slidable overlap decouples the stretch deformations and the displacements of the individual fabric layers thereby facilitating bending movements of the swimmer and improving freedom of movement of the upper torso.

In an embodiment, the first shell 4 of the lower halfsuit 3 is made of a flexible stretchable fabric having carbon fibers 26 woven into the fabric.

In an embodiment, the first shell 4 has a non-linear tensile stress-strain behavior/curve with:

a base strain range 19 in which the tensile strain of the fabric is smaller than a transition strain value 20, and

an overstrain range 21 in which the tensile strain of the fabric is greater than the transition strain value 20, wherein a tensile modulus (Young's modulus which expresses the material stiffness in terms of the tensile stress required for a 100% elongation of the material, [N/mm²]) of the fabric in the overstrain range 21 is greater than a tensile modulus of the fabric in the base strain range 19.

In an embodiment, the second shell 10 of the upper halfsuit 2 is made of a flexible stretchable fabric having a weight per unit area [g/m²] less than a weight per unit area [g/m²] of the first shell 4 of the lower halfsuit 3.

The second shell 10 of the upper halfsuit 2 may have carbon fibers 26 woven into the fabric. However, advantageously, the carbon fibre content of the second shell 10 (a mass per unit area content [g/m²]) is lower than the carbon fibre content of the first shell 4, preferably less than half the carbon fibre content of the first shell 4.

In an alternative embodiment the tensile stiffness relationship between the upper halfsuit 2 and the lower halfsuit 3 can be reversed to provide a higher upper body compression and support and a lower lower body compression but greater lower body freedom of movement.

In this embodiment, the lower halfsuit 3, i.e. the first shell 4, has, throughout its entire extension, a stretch stiffness that is lower than a stretch stiffness of the upper halfsuit 2, i.e. the second shell 10.

Similarly, the upper halfsuit 2, i.e. the second shell 10, has, throughout its entire extension, a stretch stiffness that is higher than a stretch stiffness of the lower halfsuit 3, i.e. the first shell 4.

With the exception of joining lines 16 along which fabric edges of the second shell 10 are connected and of the internally lined chest region 17, the second shell 10 of the upper halfsuit 2 has substantially uniform material properties throughout its entire extension. Possibly the second shell 10 is made of a substantially uniform fabric throughout its entire extension.

In an embodiment, the second shell 10 is made of a flexible stretchable fabric having carbon fibers 26 woven into the fabric.

In an embodiment, the second shell 10 has a non-linear tensile stress-strain behavior/curve with:

a base strain range 19 in which the tensile strain of the fabric is smaller than a transition strain value 20, and

an overstrain range 21 in which the tensile strain of the fabric is greater than the transition strain value 20, wherein a tensile modulus (Young's modulus which expresses the material stiffness in terms of the tensile stress required for a 100% elongation of the material, [N/mm²]) of the fabric in the overstrain range 21 is greater than a tensile modulus of the fabric in the base strain range 19.

In an embodiment, the first shell 4 of the lower halfsuit 3 is made of a flexible stretchable fabric having a weight per unit area [g/m²] less than a weight per unit area [g/m²] of the second shell 10 of the upper halfsuit 2.

A carbon fibre content of the second shell 10 (a mass per unit area content [g/m²]) may be higher than a carbon fibre content of the first shell 4.

In an embodiment applicable to the first shell 4 and/or the second shell 10, the carbon fibers 26 are woven into the fabric in a multiple bent configuration such that:

in a base strain range 19 in which the tensile strain of the fabric is smaller than a transition strain value 20, the carbon fibers 26 can bend and straighten out without elongation (and, hence, without, axial fiber stress and strain) and without substantially contributing to the tensile stiffness of the fabric,

in an overstrain range 21 in which the tensile strain of the fabric is greater than the transition strain value 20, the carbon fibers 26 are elongated (involving axial fiber stress and strain) and contribute to and increase the tensile stiffness of the fabric compared to its tensile stiffness in the base strain range 19.

Preferably, the tensile modulus of the fabric 3 in the overstrain range is greater than two times the tensile modulus in the base strain range, preferably, the tensile modulus in the overstrain range of the fabric 3 amounts to 3 . . . 5 times the tensile modulus in the base strain range.

The fabric may comprise twisted elastomer yarn, e.g. twisted Lycra® and/or Nylon multifilament yarn woven together with the reinforcement carbon fibers 26.

The reinforcement fibers 26 may be advantageously embodied as carbon added polyamide multifilament yarns. Such yarns can be easily woven together with other elastomeric yarns of the fabric and are adapted to create together with the remaining polymeric yarn a desired low-drag and water repellent surface texture.

In a preferred embodiment, the base threads of the fabric are polyamide-lycra® threads in which a polyamide fiber or fiber strand is twisted about a lycra® core. The reinforcement threads are polyamide-carbon-lycra® threads in which a polyamide fiber or fiber strand is coated with carbon and the carbon coated polyamide fiber or fiber strand is twisted about a lycra® core.

The reinforcement threads are woven in the fabric providing 1 warp reinforcement thread per each 54 warp steps and 2 weft reinforcement threads per each 43 weft steps.

Hence, in accordance with an embodiment, the weft direction which corresponds to a hoop (or circumferential) direction 22 of the first trunk portion 5 and/or second trunk portion 11 and/or of the thigh portions 8, comprises a significantly greater amount of directional reinforcement, than the warp direction which is oriented in a longitudinal direction 23 of the first trunk portion 5 and/or second trunk portion 11 and/or of the thigh portions 8. Accordingly, in the overstrain range 21 or generally, the fabric has a greater tensile stiffness in the weft direction than in the warp direction.

In an advantageous embodiment, in a front view, along the leg apertures 12 the second trunk portion 11 is tapered towards the second crotch portion 13 with an angle of convergence 24 of less than 120°, preferably less than 90°, e.g. approx. 60° to 75°, thereby providing an approximately triangular anterior sliding overlap area and an approximately triangular rear sliding overlap area between the upper and lower halfsuits 2,3. This improves the sliding capability of the upper halfsuit 2 on the lower halfsuit 3 in the overlap region 15 which corresponds to a lower torso region of the swimmer.

The second trunk portion 11 of the upper halfsuit 2 may further form a rear aperture 25 opposite the chest region 17, in order to lighten the upper halfsuit 2 and to improve freedom of movement.

The invention concerns also a method of using the swimsuit 1 comprising the steps of:

selecting the lower halfsuit 3 in accordance with lower body properties (e.g. size, shape properties and compression requirements) of the female swimmer,

selecting the upper halfsuit 2 in accordance with upper body properties (e.g. size, shape properties and compression requirements) of the female swimmer,

putting on the lower halfsuit 3 by slipping the swimmers' legs into the upper slip-in aperture 6 and through the thigh portions 8 of the lower halfsuit 3,

putting on the upper halfsuit 2 by pulling the upper halfsuit 2 over the lower halfsuit 3 and slipping the swimmers' arms through the shoulder apertures 15 and having the swimmers' neck extending through the neck aperture 14,

during swimming, bending the swimmers' body in a lower torso region thereof to make the upper halfsuit 2 slide with respect to the lower halfsuit 3 in an overlap region 15 therebetween.

The lower halfsuit 3 acts as a lining of the upper halfsuit 3 in the crotch and core area once both halfsuits 2, 3 are worn by the swimmer. Compression is applied by the lower halfsuit 3 to the major muscle groups (upper legs and thigh muscles and core area), providing excellent hold and support and ultimately helps the swimmer hold a desired body position in the water, for less drag, as well as reduces fatigue for tired muscles. Hence, the full advantage of an internally lined one-piece female compression swimsuit is achieved.

The upper halfsuit 2 provides less compression across the upper body, chest area and shoulders of the swimmer, allowing the swimmer to breathe more easily and to move more freely during all strokes. Hence, also the advantage of a lightweight or two-piece female swimsuit is achieved.

However the function of the swimsuit 1 of the present invention goes beyond these combined advantages: the assembly of the two halfsuits 2, 3 with slidable interface overlap engagement also works like a universal joint during the swimmers' starts off the blocks as well as during the turns off the wall. The upper halfsuit 2 moves over the surface of the lower halfsuit 3 to create a type of “hinge” which ultimately reduces restriction for the swimmer.

This way, both the muscle compression and the freedom of movement are enhanced and optimized with respect to prior art two piece swimsuits in which the two pieces are at a distance from one another and do not work together, but also with respect to prior art single piece swimsuits. In the present invention, the partial overlap and the decoupling of displacements and stretch deformations of both pieces constitute a fundamentally different hybrid concept, in contrast with prior art two-piece female swimsuits covering only distanced sections of the body. As explained, this new hybrid concept has an effect on both the swimming performance and the wearing experience.

While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications may readily appear to those skilled in the art. 

1. A female two-piece swimsuit comprising an upper halfsuit and a lower halfsuit separate from the upper halfsuit and adapted to be combined together to make the swimsuit, the lower halfsuit comprising a first shell made of a flexible stretchable fabric and forming: a tubular first trunk portion intended to cover a lower region of the torso of the swimmer and having an upper slip-in aperture and a lower end opposite the slip-in aperture, two tubular thigh portions intended to cover each an upper region of a respective thigh of the swimmer and extending from the lower end of the first trunk portion and joining each other in a first crotch portion extending between the thigh portions from an anterior side of the first trunk portion to a rear side of the first trunk portion, the upper halfsuit comprising a second shell made of a flexible stretchable fabric and forming: a second tubular trunk portion intended to cover a region of the torso and the chest of the swimmer and having two lower leg apertures intended for the swimmers' legs to extend therethrough, a second crotch portion extending between the two lower leg apertures from an anterior side of the second trunk portion to a rear side of the second trunk portion, one neck opening on an upper side of the upper halfsuit opposite the second crotch portion and intended for a swimmer's neck to extend therethrough, and two lateral shoulder openings formed on two opposite sides with respect to the neck opening and intended for the swimmers' shoulders to extend therethrough, wherein the upper halfsuit is slipped over the lower halfsuit so that the thigh portions of the lower halfsuit portion extend through the lower leg apertures of the upper halfsuit on the outside of the upper halfsuit and, in an overlap region, the second trunk portion externally wraps the first trunk portion and the second crotch portion externally wraps the first crotch portion, wherein the upper and lower halfsuits are in slidable contact to each other in said overlap region.
 2. The female two-piece swimsuit according to claim 1, wherein a sliding interface between the upper and lower halfsuits in the overlap region decouple displacements and stretch deformations of the upper halfsuit from displacements and stretch deformations of the lower halfsuit.
 3. The female two-piece swimsuit according to claim 1, wherein in the overlap region the upper halfsuit the second shell has a stretch stiffness lower than a stretch stiffness of the first shell.
 4. The female two-piece swimsuit according to claim 3, wherein the second shell has, throughout its entire extension, a stretch stiffness lower than a stretch stiffness of the first shell.
 5. The female two-piece swimsuit according to claim 4, wherein in the overlap region both the upper halfsuit and the lower halfsuit have each a single layer fabric and form together a combined double layer shell with a sliding interface between the two single layer fabrics.
 6. The female two-piece swimsuit according to claim 5, wherein the first shell has carbon fibers woven into the fabric.
 7. The female two-piece swimsuit according to claim 6, wherein the first shell an anisotropic stretch stiffness and in at least one direction a non-linear tensile stress-strain curve with a base strain range in which the tensile strain of the fabric is smaller than a transition strain value, and an overstrain range in which the tensile strain of the fabric is greater than the transition strain value, wherein a tensile modulus of the fabric in the overstrain range is greater than a tensile modulus of the fabric in the base strain range.
 8. The female two-piece swimsuit according to claim 6, wherein the second shell has a weight per unit area less than a weight per unit area of the first shell.
 9. The female two-piece swimsuit according to claim 8, wherein the second shell has carbon fibers woven into the fabric, and wherein a carbon fibre content of the second shell is lower than a carbon fibre content of the first shell.
 10. The female two-piece swimsuit according to claim 9, wherein in the first and second shells a weft direction of the fabric is oriented in a circumferential direction of the first trunk portion and of the second trunk portion and of the thigh portions and a warp direction of the fabric is oriented in a longitudinal direction of the first trunk portion and second trunk portion and of the thigh portions, wherein at least one of the first and second shells comprises a greater amount of directional carbon fibre reinforcement in said weft direction than in said warp direction.
 11. The female two-piece swimsuit according to claim 10, wherein along the leg apertures the second trunk portion is tapered towards the second crotch portion with an angle of convergence selected in the group consisting of: less than 120°, less than 90°, from 60° to 75°, thereby forming a triangular anterior sliding overlap area and a triangular rear sliding overlap area between the upper and lower halfsuits.
 12. A method of using the female two-piece swimsuit according to claim 1, comprising the steps: selecting the lower halfsuit in accordance with lower body properties of the female swimmer, selecting the upper halfsuit in accordance with upper body properties of the female swimmer, putting on the lower halfsuit alone by slipping the swimmers' legs into the upper slip-in aperture and through the thigh portions of the lower halfsuit, after putting on the lower halfsuit putting on the upper halfsuit by pulling the upper halfsuit over the lower halfsuit and slipping the swimmers' arms through the shoulder apertures and having the swimmers' neck extending through the neck aperture, during swimming, bending the swimmers' body in a lower torso region thereof to make the upper halfsuit slide with respect to the lower halfsuit in the overlap region.
 13. The method according to claim 12, comprising assembling the swimsuit from two separate parts with a sliding interface overlap and a sliding interface between the second trunk portion and the first trunk portion and the first and second crotch portions which decouple the displacements and stretch deformations of the upper and lower halfsuits by creating a multiple DOF sliding hinge.
 14. The female two-piece swimsuit according to claim 1, wherein the swimsuit is assembled from two separate parts with a sliding interface overlap and which can be put on in two separate steps.
 15. The female two-piece swimsuit according to claim 1, having a sliding interface between the second trunk portion and the first trunk portion and the first and second crotch portions which decouple the displacements and stretch deformations of the upper and lower halfsuits by creating a multiple DOF sliding hinge. 